Anti-fluoride campaigners are crying foul over what they claim is a rushed attempt to push through controversial legislation over the holiday period.
If passed, the law would cement the current situation, allowing councils to add the chemical to local water supplies.
Currently councils have the power to put fluoride in community water supplies in a bid to reduce tooth decay.
Mary Byron is on a tank system and is absolutely against putting fluoride in drinking water.
"It's an unhealthy substance for us to be taking into our body," she says.
But Dr Robin Whyman disagrees, arguing: "We get reductions of around 20 to 40 percent, when we add fluoride to the water, in those decay levels."
Anti-fluoride campaigners have been to court arguing the chemical's components are subject to the Medicines Act and legally it can't be added to water supplies.
The court ruled fluoridation was legal but now the Health Ministry wants to clarify the current law.
"It would make it very clear that under the Medicines Act, at the low concentrations we're talking about for community water fluoridation, fluoride in that regard is not a medicine," Dr Whyman says.
Anti-fluoride campaigners say holding public submissions on the proposed amendment over the New Year period is an attempt to rush it through while everyone is on holiday.
The anti brigade is appealing the court decision in a few months and says the Health Ministry's attempt to wrap up public submissions on the matter before then is unfair.
"It's really disappointing it just doesn't give us enough time to put in a proper submission or to let people know what's going on. It's just circumventing all due process," Ms Byrne says.
Cabinet will make the final decision on the proposed amendment later this month.